Re: [PATCH v2 14/17] riscv: dts: microchip: add fpga fabric section to icicle kit

Hi Conor,

On Fri, Dec 17, 2021 at 4:32 PM [off-list ref] wrote:

On 17/12/2021 13:43, Geert Uytterhoeven wrote:

quoted

On Fri, Dec 17, 2021 at 10:33 AM [off-list ref] wrote:

quoted

From: Conor Dooley <conor.dooley@microchip.com>

Split the device tree for the Microchip MPFS into two sections by adding
microchip-mpfs-fabric.dtsi, which contains peripherals contained in the
FPGA fabric.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Thanks for your patch!

quoted

--- /dev/null
+++ b/arch/riscv/boot/dts/microchip/microchip-mpfs-fabric.dtsi

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Copyright (c) 2020-2021 Microchip Technology Inc */
+
+/ {
+       corePWM0: pwm@41000000 {
+               compatible = "microchip,corepwm";
+               reg = <0x0 0x41000000 0x0 0xF0>;
+               microchip,sync-update = /bits/ 8 <0>;
+               #pwm-cells = <2>;
+               clocks = <&clkcfg CLK_FIC3>;
+               status = "disabled";
+       };

I'm wondering if these should be grouped under a "fabric" subnode,
like we have an "soc" subnode for on-SoC devices? Rob?

BTW, do you already have a naming plan for different revisions of
FPGA fabric cores?

Not yet (assuming you mean specifically how we will handle it in the
device tree) - although i was talking to someone about it yesterday.
It's possible that we might handle that via a register, but if you have
a suggestion or some precedence that you're aware of that would be useful.

The actual naming convention of the IP cores themselves, yeah. I will
dig it up for you on Monday.

I meant what if corepwm is enhanced, and how to detect that?

SiFive uses an integer version number, even for hard cores[1].
OpenCores uses an "-rtlsvnN" suffix (isn't svn dead? ;-)
No idea what e.g. LiteX and Microwatt are planning.

[1] Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt


Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds